First a note on geography as it may be helpful for others trying to answer the question who might not be familiar with the area:
Dufferin County was not officially formed until 1881 so technically it should be Mono Township, Simcoe County, Ontario, Canada. (except possibly for the Elizabeth born 1808 since we do not know if she died before or after 1881).
Even though Dufferin County was formed in 1881 it did not become a distinct census district until 1911. Any enumerations for Mono prior to that year should be found in the Simcoe County Census District.
As far as records I have not found anything useful in answering your question but did find some pieces of information you may be interested in being aware of as they may point to different Howard families being resident in the area (of course it could equally point to a re-uniting of branches of one Howard family)
There is a database entry on the Library and Archives Canada Website for a James Howard emigrating to Mono Mills (via Toronto) in 1847.
There is a land petition by a Samuel Howard, residing at Albion Twp. in 1835, for land in Mono Township.